If you are calling Federal Income Tax “taxes” then they only make up 27.6% of government revenue. The other 72% is already spread fairly evenly amongst everybody. As for the Federal Income Tax portion of the tax bill:

Total Tax Revenue for all levels of government in 2009: $4,353 Billion

Federal Income tax:

At or Below the Poverty Line (Individual Annual Income less than $16,000)
Number of Returns 11,592,357 10.4%
Taxable Income $37 Billion 0.7%
Tax Generated $3.6 Billion 0.34%

Middle Income (Individual Annual Income more than $16,000 but less than $200,000)
Number of Returns 92,026,036 85.2%
Taxable Income $3,555 Billion 62.9%
Tax Generated $546 Billion 50.5%